Discrete modes of social information processing predict individual behavior of fish in a group

TL;DR

This study reveals that individual zebrafish alternate between active and passive social information processing modes, and modeling these modes improves predictions of their behavior and emergent group dynamics.

Contribution

The paper introduces a multi-modal behavioral model that explicitly accounts for active and passive modes, enhancing the prediction of individual and group fish behavior.

Findings

Fish switch between active and passive modes independently.

Model predicts individual fish behavior with high accuracy.

Emergent group behavior occurs despite uncorrelated mode switching.

Abstract

Individual computations and social interactions underlying collective behavior in groups of animals are of great ethological, behavioral, and theoretical interest. While complex individual behaviors have successfully been parsed into small dictionaries of stereotyped behavioral modes, studies of collective behavior largely ignored these findings; instead, their focus was on inferring single, mode-independent social interaction rules that reproduced macroscopic and often qualitative features of group behavior. Here we bring these two approaches together to predict individual swimming patterns of adult zebrafish in a group. We show that fish alternate between an active mode in which they are sensitive to the swimming patterns of conspecifics, and a passive mode where they ignore them. Using a model that accounts for these two modes explicitly, we predict behaviors of individual fish with high accuracy, outperforming previous approaches that assumed a single continuous computation by individuals and simple metric or topological weighing of neighbors behavior. At the group level, switching between active and passive modes is uncorrelated among fish, yet correlated directional swimming behavior still emerges. Our quantitative approach for studying complex, multi-modal individual behavior jointly with emergent group behavior is readily extensible to additional behavioral modes and their neural correlates, as well as to other species.